Minimum Control Measure 4: Construction Site Stormwater Runoff Control
Polluted runoff from construction sites often flows through MS4 systems into local lakes, rivers and streams. Pollution from these sites can cause physical, chemical and biological harm to waters. Sediment is usually the pollutant of concern, but construction sites can generate other pollutants (see list below).
Sediment losses from construction sites are typically 10 to 20 times greater than from agricultural lands, and 1,000 to 2,000 times greater than from forest lands. In a short time, construction sites can contribute more sediment to streams than would have been deposited naturally over several decades. Excessive sedimentation can quickly fill rivers and lakes, destroying aquatic habitats and causing flooding problems.
Pollutants Commonly Discharged From Construction Sites
- Oil and grease
- Concrete truck washout
- Nitrogen (fertilizer)
- Construction debris
- Solid and sanitary wastes
- Phosphorous (fertilizer)
- Construction chemicals
Develop, implement, and enforce a program to reduce pollutants in any stormwater runoff to the small MS4 from construction activities that result in a land disturbance of one acre or more.
Include construction activities disturbing less than one acre in the program:
- If it is part of a larger common plan of development or sale, or
- If controlling such activities in a particular watershed is required by DEC.
Develop a program that, at a minimum, provides equivalent protection to the NYS SPDES General Permit for Stormwater Discharges from Construction Activities (GP-02-01). The program must include the development and implementation of:
- A law or other regulatory mechanism to require erosion and sediment controls;
- Requirements for construction site operators to implement erosion and sediment control management practices;
- Sanctions to ensure compliance;
- Requirements for construction site operators to control waste (i.e., discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste) at the construction site that may cause adverse impacts to water quality;
- Procedures for site plan review that incorporate consideration of potential water quality impacts and review of individual pre-construction site plans to ensure consistency with local sediment and erosion control requirements;
- Procedures for receipt and consideration of information submitted by the public;
- Procedures for site inspections and enforcement of control measures; and
- Education and training measures for construction site operators about requirements.
Develop measurable goals and select appropriate management practices to ensure the reduction of all pollutants of concern in construction stormwater discharges tributary to the MS4's system to the maximum extent practicable.
MS4s establish local law or ordinance to reduce pollutants in stormwater runoff from construction activities.
MS4s conduct construction site plan reviews and routine inspections.
Erosion and sedimentation are controlled through detailed plans prepared in accordance with the construction permit, GP-02-01.